The optimum proportion of hygroscopic properties of modified soil composites based on orthogonal test method

Abstract

Abstract Most published works have considered the influence of a single factor on the thermal or hygroscopic properties of the modified soil materials, but few studies have focused on the influence of multi-factor. Therefore, an L9 (34) orthogonal array test design was adopted in this study to investigate the effects of cement, lime, fly ash, and moisture on the hygroscopic properties of modified soil composites. They were chosen as chemical additives because they are the most common and widely used industrial building materials in the construction of modern buildings. Based on results from range analysis and mean square deviation analysis, the important order of the four factors on the hygroscopic properties was achieved, then the optimum proportion is found. The results show that cement has the most obvious effect on the equilibrium moisture content in 52.89% relative humidity (RH) among the four factors, and fly ash flow is second, moisture content has a minimal effect. By optimizing the parameters, when the cement content was 7%, lime content was 5%, fly ash content was 4% and the moisture content was 10%, the highest average equilibrium moisture content of 1.625% was obtained. The optimized modified soil composites have excellent hygroscopic properties and compressive strength meets the corresponding safety requirements, so it has potential for application and development in the field of soil architecture.